<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>圆角</title>
    <style>
        .box1{
        width: 100px;
        height: 100px;
        background-color: green;
        border-radius: 10px;
        }
        .box2{
        width: 100px;
        height: 100px;
        background-color: black;
        border-radius: 50%;
        }
    </style>
</head>
<body>
    <div class="box1"></div>
    <div class="box2"></div>
</body>
</html>